Ben Wight wrote:
> I think this is what they are called, the out of round (oval) chain rings that from what I
> understand allow more torque to be applied for a greater range of the revolution of the
> chain wheel.
> Is the use of these chain wheels common? Are they used much in racing? If not, why?
Because they were a crock. You can just about make a case that it's a good idea to use an oval
chainring to increase the gear in the middle of the pedal stroke and decrease it to get the foot
over top dead center more easily, though nobody has ever been able to show that cyclist's go
measurablt faster with such a setup. However, Biopace increased the gear at the top of the stroke
and decreased it in the middle.
Racers, used to spinning, hated the way it felt, and mountainbikers didn't like the fact that it
forced a 28t inner ring when every sensible person used a 24. This is in the days when 12-28
clusters were standard, and 110/74 pitch chainsets meant 24 was as low as you could go.
And some people with dodgy knees found it made them worse.
Shimano quietly dropped it when shaped teeth and shift gates for front indexing were introduced,
claiming they couldn't get the shifting to work yet, but it would be back. Anyone holding their
breath is now long dead and very smelly.
John Stevenson Cyclingnews.com